NGC 3631 is a face on spiral galaxy located in the constellation of Ursa Major. Located some 50 million light years away, on March 13, Ron Arbour discovered a supernova in this galaxy. Currently around magnitude 15, it is easily visible in the galaxy. It was determined that this was a type 1b supernova, which is a massive star that underwent a core collapse. These are often Wolf-Rayet stars that have blown off most of their outer layers of hydrogen.

Imaged with the ED80CFT refractor, and Atik 314L+ mono ccd, it consists of 9 x 300 second images through R/G/B filters, and 39 x 300 second luminance images.